The present disclosure generally relates to a gripper assembly for a manipulator and methods for using the gripper assembly. More particularly, the present disclosure relates to an insulated gripper assembly of a manipulator for manipulating metal ingots during forging.
In metal forging processes, a mechanical hand, also known as a manipulator, has to pick up a rough or part-finished component and transfer it to a downstream work station. The metal parts begin as metal ingots that are heated in furnaces to temperatures over 1500 degrees Fahrenheit (F). As such, manipulators must be used to then transfer the metal ingots (also known as mults or blockers) to downstream work stations in the process, such as the forging dies, cooling stations, and the like.
Such manipulators are known in forging processes and generally include, in their broadest form, a mechanical arm having at least two cooperating jaws or clamping devices positioned at one end thereof. These clamping devices can also be known as gripper assemblies. Gripper assemblies are generally arranged in diametrically opposed pairs and the manipulator includes an actuator means for moving each pair in unison and with equal force between retain and release positions. The actuators or displacement means, such as piston-cylinder units, act directly or by way of wedges, links or push rods, upon the gripper assembly to effect closure of the gripper assemblies about the heated part. Current manipulators typically comprise robotic arms able to move in several planes with at least one gripper pair disposed thereon being able to pick up the hot metal part, transfer it to another work station, and, in some cases, rotate the part to a desired position for placement in the work station.
During transfer of the metal ingot from one portion of the forging process to another, such as from the furnace to the die, heat is transferred from the metal ingot to the gripper assembly of the manipulator. The manipulators have a lower temperature than the metal ingots and, therefore, even with a short transfer time, significant heat is transferred from the hot ingot to the cooler manipulator. Transfer of heat from the metal ingot is undesirable, because the metal needs to be kept at a certain, uniform temperature in order for proper formation of the part into the desired shape in the forging process. When heat is lost from those portions of the ingot in contact with the manipulator, the metal ingot will have an uneven temperature profile. The differences in temperature throughout the metal ingot can cause problems (e.g., irregularities) in the physical characteristics of the forged part. This problem can be particularly acute in the forging of smaller parts that will lose heat more quickly than large pieces of metal. Moreover, repeated cycles of heating and cooling the gripper assemblies and manipulator arms can degrade components over time.
Thus, it is desirable for the metal ingots in a forging process to be transferred from one portion of the process to the next while maintaining a substantially uniform temperature profile throughout the metal. As such, there is a need for a gripper assembly and method that substantially reduces the heat transfer between a metal ingot and the manipulator when transferring parts in the forging process.